Data terminal with automatic response feature

ABSTRACT

A data terminal which transmits binary-coded indicia representing characters in response to the operation of keys of a keyboard is provided with means different from the keyboard for automatically transmitting the representations of a particular plurality of characters in response to a remote inquiry.

United States Patent 1191 Jacobson et al.

1451 July 3, 1973 [54] DATA TERMINAL WITH AUTOMATIC 3,248,696 4/1966Bloch 340/65 S SP NS F AT E 3,588,371 6/1971 Dal Monte... 325/55 RE 0 EE UR 3,232,404 2/1966 Jones, Jr. 340/35 E Inventors: Allen Jacobson, y.-l; 3.291.910 12/1966 Nicklas et al. 178/26 R Maurice J. Epstein,Ardsley, NY. 3,493,928 2/1970 Juliusburger 340/365 E [73] Assignee:Computer Transceiver Systems, Inc.,

Paramus, NJ. Primary Examiner-Thomas W. Brown [22] Filed: June 4, 1971Att0rneyHane, Baxley & Spiecens [21] Appl. N0.: 150,009

[56] References Cited UNITED STATES PATENTS 3,531,772 9/1970 Dalyai etal 340/163 DECODER g5 [57] ABSTRACT A data terminal which transmitsbinary-coded indicia representing characters in response to theoperation of keys of a keyboard is provided with means different fromthe keyboard for automatically transmitting the representations of aparticular plurality of characters in response to a remote inquiry.

10 Claims, 4 Drawing Figures M7 TO REMOTE TERMINAL 0+-- PRJNTER &

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INVENTORS ALLEN G. JACOBSON BY MAURlCE J. EPSTEIN ATTORNEYS PAIENTEBJIJLam 3.743763 man 07 2 KEYBOARD 1 8 JUNCTION BOX 2 4 KS! I J1? y x o oKS2- K2 J2 y I FROM 1 O I F Q.) KEYBOARA f l l I 15 I I TO i K2 5ENcoDER 1 TO I |G l muNcnoN i i KN BOX i KSN- E ,KRN J 7 L KN JN VO"HKLI L Sk/Zi ii is S4 H; 0 b o 53 KLL L if 'FROM STEP COUNTER g9 F0 FROMI FLIP-FLOP 23 FIG. 3

TO MODEM 1 2 AND PRINTER E L i E! E E3 4 E5 ENCODER :2 OR To AND cm 25 3ES swcoomc; MEANS w FROM JUNCTION BOX g5 DATA TERMINAL WITH AUTOMATICRESPONSE FEATURE THE INVENTION This invention pertains to data terminalsand more particularly to data terminals with automatic answer backfacilities.

In data communication networks wherein data terminals converse with eachother it is often necessary for the terminals to identify themselves. Insome networks the terminal operators stroke in the identification.However, at unattended terminals automatic means must be provided torespond to an identification inquiry. Heretofore, special mechanicalcode generators have been included in the terminal to provide theautomatic response. Such code generators added to the complexity of theequipment and often duplicated some of the existing parts of theterminal.

It is an object of the invention to provide a data terminal with anautomatic identification response facility which utilizes most of thepreexisting elements of the terminal and only adds a minimum of extraequipment.

Briefly, the invention contemplates a data terminal for transmittingbinary-coded combinations of indicia representing characters comprisinga plurality of selectively operable means, each of which when operatedgenerating at least one first signal associated with a differentcharacter. An encoder means connected to the selectively operable meansencodes each of the first signals into a unique binary-coded combinationof second signals. Means convert the second signals to indicia fortransmission. In parallel with and independent of the plurality ofselectively operable means is controllably operable means forautomatically generating a predetermined sequence of the first signalswhich are also encoded to combinations of second signals by the encodermeans.

Other objects, the features and advantages of the invention will beapparent from the following detailed description when read with theaccompanying drawing which shows, by way of example and not limitation,apparatus for realizing the invention. In the drawing:

FIG. 1 is a block diagram of a data terminal according to an exemplaryembodiment of the invention;

FIG. 2 is a schematic diagram of the keyboard of the data terminal ofFIG. 1;

FIG. 3 is a schematic of the junction box in the data terminal of FIG.1; and

FIG. 4 is a block diagram of the encoder of the data terminal of FIG. 1.

The embodiment of the invention will be described assuming positivelogic wherein the more positive voltage (a high signal) represents the 1state; and the less positive voltage (a low signal) represents thestate.

Data terminal of FIG. 1 has for its main elements the modem 12, theprinter 14, the encoder 16, the keyboard 18 and an automatic responsegenerator centered around step counter 20 and flip-flop 22. In normal,i.e., non-automatic operation when an operator strokes a key of keyboard18 a high signal is generated on its associated one of the lines Kl toKN which passes, via junction box and a corresponding line J1 to IN, toan input terminal of encoder 16. Encoder 16 transforms the signalreceived at the particular input to a corresponding binary-codedcombination of high and low signals on the seven lines of cable E1-E7,assuming a seven-bit code for the characters. The coded combination ofsignals on the lines El-E7 can be fed to printer 14 which prints a hardcopy representation of the character under control of a strobe signal online PS from encoder 16, via line E8, AND-curcuit 25 and OR- circuit 26.

In addition the coded combination of signals on the lines El-E7 are fedto modem 12 where they are converted to a coded combination of tonesignals which are fed, via, say, a telephone line to the receiver of aremote terminal (not shown). During normal reception of data, modem 12receives the coded combinations of tone signals from a remote terminal,converts them to binary-coded combinations of high and low signals whichare fed in parallel via the seven lines of cable M1 to M7 to printer 14.Printer 14 accepts the signals under control of a strobe signal on linePS from modem 12, via lines MS and via OR-circuit 26.

For automatic response operation flip-flop 22 is set to the l-state, bya signal from OR circuit 32. Automatic response can be initiated eitherby the operator at data terminal l0'by closing switch SW1 and applying ahigh voltage H to one input of OR-circuit 32, which normally receives alow voltage L via resistor R1, or from the remote terminal as indicatedby a signal on line DS connected to the other input of OR-circuit 32from the output of decoder 34. The inputs of decoder 34 are connected tothe seven output lines M1 to M7 of modem 12. When modem 12 receives fromthe transmitter of the remote terminal (not shown) an inquiry character(a unique coded combination of tone signals) requesting terminal 10 toidentify itself, decoder 34 senses the character and emits a pulse online DS.

In either case, when flip-flop 22 is set to the l-state by a signal atits S-input from the output of OR-circuit 32, line F1, connected to thel-output, goes high and line F0, connected to the O-output, goes low.Since line F1 is connected to one input of two-input AND-circuit 28 apath is connected from the clock 40 whose output is connected, via lineCK, to the second input of AND- circuit 28 to the step input S of stepcounter 20 which is connected to the output of AND-circuit 28. It willbe assumed that step counter 20 has five stages and that clock 40 is afree-running pulse generator having a pulse repetition rate below themaximum band transmission rate. The first pulse entering step counter 20activates its first stage generating a signal on line 81 which is fed tojunction box 24 where it is connected to one of the lines J1 to IN, theparticular line being the line representing the first character of theautomatic response. In a similarmanner the second, third and four clockpulses sequentially generate signals of lines S2, S3 and S4 by steppingcounter 20 to activate the second, third and fourth stages. Similarlylines S2, S3 and S4 are also connected to the appropriate ones of thelines J1 to JN representing the remaining characters of the response.The fifth stepping pulse from clock 40 steps the counter to the fifthstage, generating a signal on line S5 which is connected to the resetinput R ping the signal on line Fl which blocks AND-circuit 28 andraising the signal on line F0. The automatic response cycle isterminated. However, while flip-flop 22 was set the signal on line F0was low. This line is connected to keyboard 18 for controlling itsoperation. As will hereinafter become apparent, keyboard 18 requires ahigh signal on line F0 for it to operate. Therefore, whenever flip-flop22 is set to the l-stage, i.e., during the automatic response cycle,keyboard 18 is prevented from operating.

Similarly, when switch SW2 is closed (as shown) the state of flip-flop22 controls the operation of printer 14. In particular line F isconnected to one input of twoinput AND-circuit 25 whose other input isconnected to line ES from encoder 16. It will be recalled that encoder16 emits a pulse on lines ES each time it encodes a signal from junctionbox 24. The output from AND- circuit 26 is connected via OR-circuit 26and line PS to the strobe input S of printer 14. Since printer 14 willonly print the character represented by the signals on lines E1 to E7from encoder 16 when it receives a strobe pulse and since duringtransmission the strobe pulses are on line ES from encoder 16, thesignal level on line F0 controls the operation of printer 14. Therefore,during the automatic response cycle when flipflop 22 is set to thel-state printer 14 does not hardcopy record the transmitted characters.However, by opening switch SW2 the control of AND-circuit 25 byflip-flop 22 is disabled and printer 14 always operates.

The details of the various elements of the data terminal will now bedescribed.

In FIG. 2 there is shown one possible embodiment of keyboard 18 whichcomprises N key operated switches KS1 to KSN, each representing adifferent character. Since all the switches are the same a typicalswitch KS1 associated with the character 1 will be described. Themovable contact of switch KS1 is connected to the movable contact ofcontact set KCC of relay KLl and the fixed contact of switch KS1 isconnected to line K1 and via a resistor KRl to a low voltage line L.Assume that the movable contact of set KCC is against the fixed contactconnected to the high voltage line H, i.e., the normal condition. Then,whenever an operator depresses the key associated with character 1 thesignal on line Kl goes from low to high indicating the entry ofcharacter l. When the operator releases the key the switch springs backto the open state and line K1 reverts to the low voltage. When thesignal on line F0 goes low current flows through the coil KLL of relayKLl which attracts the moveable contact of set KCC to the fixed contactconnected to the low voltage L. Then the movable contacts of all the keyoperated switches KS1 to KSN are connected to a low voltage. Thus,regardless of the position of switch KS1, line Kl will be low and nocharacter can be manually entered.

Of course it should be realized that other types of keyboards can beused. For example, keyboards whose switches generate more than onesignal when depressed can be used as well as keyboards with caseshifting facilities. In addition, instead of using a relay to controlthe operation of the keyboard, one could profitably use solid stateswitches.

The junction box 24 shown in FIG. 3 provides parallel connections fromcertain lines K1 to KN and S1 to S4 to lines J1 to JN. In particular,each line K1 to KN is through connected, via an isolation diode, to acorresponding line J1 to JN. To add in the automatic response charactersthe lines S1 to S4 are connected, via isolation diodes, to theappropriate lines J1 to JN. In the example shown the automatic responseword is assumed to be 112. Therefore line S1 is connected to line J1,line S2 to line J1 and line S3 to line J2. Line S4 remains unconnected.While only four lines S1 to S4 are shown, much longer answer back orresponse words could be generated by having more stages to counter 20and more lines SN could be used. The disclosed junction box mates withkeyboard 18. If other keyboards were used corresponding modificationswould be made to the junction box. Furthermore, a discrete junction boxplug board neednot be employed but the required connections could befixed wired from the lines SN to appropriate lines directly on keyboard18.

The encoder 16 shown in FIG. 4 includes an encoding means which can be aconventional diode matrix type encoder or a read-only memory typeencoder which emits a unique coded combination of signals in parallel onlines E1 to E7 in response to a signal on each of the lines J1 to JN. Inaddition, each of the lines E1 to E7 is connected to an input ofOR-circuit 52 so that a signal is present on line ES, connected to theoutput of OR-circuit 52, each time a signal is encoded which can be usedas a printer strobe. Modern 12 can be any of many conventionalmodulator-demodulators. For example, it can be of the type wherein inthe modular section the coded combination of signals on lines E1 to E7are fed in parallel to seven parallel tone generators each operating ata unique frequency and in the demodulator section there are seven tunedamplifiers in parallel, each tuned to one of the unique frequencies.There can also be used serial type modems wherein, in the modulatorsection, the seven parallel signals on lines E1 to E7 are serialized andused to shift a carrier signal between two frequency tones and in thedemodulator section the frequency shift keyed tones are demodulated toserial pulses which are then distributed in parallel.

The printer can take many forms. A particularly useful printer is madeby the National Cash Register Company and available as Model EM-Tl-Ol.The modern can take many forms such as the DATASETS manufactured by theAmerican Telephone and Telegraph Co. While only one embodiment has beenshown and described in detail there will now be obvious to those skilledin the art many modifications and variations satisfying many or allother objects but which do not depart from the spirit of the inventionas defined by the appended claims. I

In particular, although the invention has been described with respect toa manual input terminal, it can be used with data terminals havingmagnetic and paper tape entries or even with remote telemetering dataacquisition terminals.

What is claimed is:

l. A data terminal for transmitting binary-coded combinations of indiciarepresenting characters comprising a plurality of selectively operablemeans, each of said selectively operable means, when operated,generating at least one first signal associated with a differentcharacter respectively, an encoder means for encoding each of said firstsignals into a unique binarycoded combination of second signals, meansfor connecting said plurality of selectively operable means to saidencoder means, means for converting said second signals to indicia fortransmission, and controllably operable means independent of saidplurality of selectively operable means for automatically generating agroup of said first signals in a predetermined sequence, and means foroperatively connecting said controllably operable means to said encodermeans.

2. The data terminal of claim 1 wherein said plurality of selectivelyoperable means is a keyboard device and further comprising means forpreventing the generation of said first signals by said keyboard devicewhen said controllably operable means is automatically generating saidgroup of said first signals in the predetermined sequence.

3. The data terminal of claim 2 further comprising printer means forconverting said binary-coded combinations of second signals to printedcharacters and means for preventing the operation of said printer meanswhen said controllably operable means is automatically generating saidgroup of said first signals in the predetermined sequence.

4. The data terminal of claim 1 further comprising manually operablemeans for activating said controllably operable means.

5. The data terminal of claim 1 further comprising means for receivingremotely generated binary-coded combinations of indicia and means forsensing when a particular remotely generated binary-coded combination ofindicia is received by said receiving means for activating saidcontrollably operable means.

6. The data terminal of claim 5 further comprising manually operablemeans for activating said controllably operable means.

7. The data terminal of claim 6 wherein said plurality .of selectivelyoperable means comprise a keyboard device with a plurality of manuallyoperable keys and further comprising means for preventing the generationof said first signals by said keyboard device when said controllablyoperable means is automatically generating a group of said first signalsin a predetermined sequence.

8. The data terminal of claim 7 further comprising printer means forconverting said binary-coded combinations of second signals to printedcharacters and meanS for preventing the operation of said printer meanswhen said controllably operable means is automatically generating saidgroup of said first signals in the predetermined sequence.

9. The data terminal of claim 1 wherein said plurality of selectivelyoperable means comprise a keyboard device having a plurality ofkey-operated switches, each of said switches being connected to at leastone output line, said encoder means includes a plurality of inputterminals connected to said output lines and said controllably operablemeans includes stepping means for emitting a signal from each of aplurality of output terminals in a sequential order, the outputterminals of said stepping means being connected to selected inputterminals of said encoder means.

10. The data terminal of claim 9 further comprising means for receivingremotely generated binary-coded combinations of indicia and means forsensing when a particular remotely generated binary-coded combination ofindicia is received by said receiving means for activating saidcontrollably operable means.

1. A data terminal for transmitting binary-coded combinations of indiciarepresenting characters comprising a plurality of selectively operablemeans, each of said selectively operable means, when operated,generating at least one first signal associated with a differentcharacter respectively, an encoder means for encoding each of said firstsignals into a unique binary-coded combination of second signals, meansfor connecting said plurality of selectively operable means to saidencoder means, means for converting said second signals to indicia fortransmission, and controllably operable means independent of saidplurality of selectively operable means for automatically generating agroup of said first signals in a predetermined sequence, and means foroperatively connecting said controllably operable means to said encodermeans.
 2. The data terminal of claim 1 wherein said plurality ofselectively operable means is a keyboard device and further comprisingmeans for preventing the generation of said first signals by saidkeyboard device when said controllably operable means is automaticallygenerating said group of said first signals in the predeterminedsequence.
 3. The data terminal of claim 2 further comprising printermeans for converting said binary-coded combinations of second signals toprinted characters and means for preventing the operation of saidprinter means when said controllably operable means is automaticallygenerating said group of said first signals in the predeterminedsequence.
 4. The data terminal of claim 1 further comprising manuallyoperable means for activating said controllably operable means.
 5. Thdata terminal of claim 1 further comprising means for receiving remotelygenerated binary-coded combinations of indicia and means for sensingwhen a particular remotely generated binary-coded combination of indiciais received by said receiving means for aCtivating said controllablyoperable means.
 6. The data terminal of claim 5 further comprisingmanually operable means for activating said controllably operable means.7. The data terminal of claim 6 wherein said plurality of selectivelyoperable means comprise a keyboard device with a plurality of manuallyoperable keys and further comprising means for preventing the generationof said first signals by said keyboard device when said controllablyoperable means is automatically generating a group of said first signalsin a predetermined sequence.
 8. The data terminal of claim 7 furthercomprising printer means for converting said binary-coded combinationsof second signals to printed characters and meanS for preventing theoperation of said printer means when said controllably operable means isautomatically generating said group of said first signals in thepredetermined sequence.
 9. The data terminal of claim 1 wherein saidplurality of selectively operable means comprise a keyboard devicehaving a plurality of key-operated switches, each of said switches beingconnected to at least one output line, said encoder means includes aplurality of input terminals connected to said output lines and saidcontrollably operable means includes stepping means for emitting asignal from each of a plurality of output terminals in a sequentialorder, the output terminals of said stepping means being connected toselected input terminals of said encoder means.
 10. The data terminal ofclaim 9 further comprising means for receiving remotely generatedbinary-coded combinations of indicia and means for sensing when aparticular remotely generated binary-coded combination of indicia isreceived by said receiving means for activating said controllablyoperable means.